The present invention relates generally to a cap for a gas burner. More particularly, the present invention relates to a cap for a gas burner, and a spill resistant gas burner assembly incorporating such a cap.
Gas burner assemblies have been widely used in cooking appliances such as free standing cooking ranges, cooktop units. Such gas burner assemblies often include a gas burner unit and a cap disposed on the gas burner unit. As is known in the art, included in the gas burner unit is an ignition system, such as, for example, a piezoelectric starter, that provides a spark for igniting gas flowing out of the gas discharge ports of the gas burner unit. Also as is known in the art, the cap can be made an integral part of the gas burner unit. Alternatively, it can be a removable part sitting on the gas burner unit. In the latter configuration, preferably the cap and the gas burner unit together define a plurality of gas discharge ports along a lateral wall of the gas burner unit (the cap defines the top of each gas discharge port). These are known in the art, and therefore will not be discussed in detail herein.
One common problem with gas burner assemblies is that liquids in a cooking vessel or utensil can be heated to such a degree that they may boil over from the top of the cooking vessel and fall onto the cap. Such boiled-over liquid, referred to as “spillover” or “spill” herein, can extinguish the flames of the gas burner unit and even foul the ignition system. In an attempt to prevent a relatively small amount of spillover from flowing into and extinguishing the flames, the cap often has a recessed portion on its top surface to confine the spillover therein. Alternatively and/or additionally, the cap often has a diameter that is slightly greater than that of the gas burner unit so that the cap can steer or direct the spillover away from the gas discharge ports of the gas burner unit.
While these caps may operate with some degrees of success, they have various disadvantages. For example, when a relatively large amount of spillover falls onto a known cap discussed above, flames are often extinguished. Moreover, despite efforts with known caps, spillover continues to foul the ignition system because of surface tension between the spillover and the cap as well as dynamics of the spillover.
A very large cap can be used to better shield the gas burner unit from spilled liquids. However, this large cap negatively impacts the combustion of the gas flowing out of the gas discharge ports because the flame has to travel almost horizontally a significant distance under the cap, thereby creating excessive flame impingement. It also reduces the heating efficiency of the gas burner assembly because a significant amount of the flame is below the cap and the heat is transferred to the cap rather than the cookware. FIG. 1 illustrates a side view of an exemplary gas burner assembly 100 wherein a large cap 110 is positioned on a gas burner unit 130. As illustrated in FIG. 1, flame 120 extends a significant distance under the cap 110 before being directed upward to heat a cooking utensil (not shown). This substantially reduces the heating efficiency of the gas burner assembly 100. Also shown is an igniter 140 that provides a spark for igniting the gas flowing out of the gas burner unit 130. As illustrated in FIG. 2, the cap 110 may be spaced high above the gas burner unit 130 by spacers 210. In this configuration, the combustion of the gas flowing out of the gas discharge ports may be improved. However, the cooking utensil is positioned further away from the flame 120′. As a result, the heating efficiency of the gas burner assembly 200 is again reduced.
Hence, there is a need in the industry for a cap which can safely steer or direct spillover away from the ignition system and the flame without substantially reducing the heating efficiency of the gas burner assembly.